Computer security systems are often based on the basic access control model, which provides a foundation of secrecy and integrity security procedures. See, for example, the 1974 article by Butler Lampson, "ACM Operating System Reviews," Vol. 8, No. 1, January 1974, pp. 18-24. The elements of this model are:
Objects, which are resources such as files, devices, or processes. PA1 Request to perform operation on objects. PA1 Sources for requests, which are principals. PA1 A reference monitor that examine each request for access to a specified object and decides whether to grant it.
The reference monitor bases its decision on the object, the principal making the request, the operation in the request, and a rule that says what principals may perform that operation.
To do its work, the reference monitor needs a trustworthy way to know the access control rule and the source of the request. Usually the access control rule is attached to the object; such a rule is called an access control list or ACL. For each operation, it specifies a set of authorized principals, and the reference monitor grants a request if its principal is trusted at least as much as one of the authorized principals for the requested operation.
It should be understood that operation of the reference monitor is separated and distinct from other security issues, such as whether a requestor is who he/she/it claims to be. That type of security is typically provided by using encryption and digital signature techniques, as will be understood by those skilled in the art. The present invention is directed at systems and methods for governing access to ojbects in distributed computer system that allow for "compound principals". The concept of compound principals, while discussed in detail below, is also explained in U.S. Pat. application Ser. No. 07/589,923, filed Sep. 28, 1990, entitled Compound Principals in Access Control Lists, hereby incorporated by reference.